I found a decent deal on an SX-850 (decent these days anyway) on eBay. I wish I could find some of the deals that I've read about on this forum, but I'm just not that lucky. The guy who sold it indicated that one of the channels was blown out when he move a speaker while it was playing and the wires crossed. Well when I got it, I found both channels had most of the output transistors blown, so the one channel out advertisement was perhaps a bit misleading. I've got the output transistors on order from Mouser. I've pulled the heatsink and the power amp board out of the chassis so that I could work on them more easily. On the power amp board I've replaced all of the electrolytics and the "greenies". I also replaced the 2SA726 transistors as I've read that these tend to get noisy over time. I also replaced the 150ohm 2watt resistors as a couple of them looked scorched. I've check all of the other components and everything looks fine, however, there is a little scorching on the underside of the PCB where two of the driver transistors are located. The transistors tested fine. I have all of the replacement transistors (based on Mark the fixer's list) on-hand to change out anything on this board, and I'd like to do whatever is necessary before I install it back in the chassis. My question is, should I proactively change out any of these other transistors on the main power amp board, or leave the originals in place? Part of me wants to change them so that they are new and fresh, the other part of me wants to stick with the originals because the replacements are always going to be a little different. Recommendations please.